The present invention relates to the production of monohalogenated olefins directly from halogen-containing alkanes. More particularly, it relates to the production of vinyl chloride by oxydehydrogenation of ethyl chloride in contact with a catalyst which provides high yields of the vinyl chloride product.
In many processes for producing vinyl chloride, a co-product of the reaction is ethyl chloride. The ethyl chloride may be separately recovered as such or may be recycled in some processes for further chlorination to dichloroethane and ultimate conversion to vinyl chloride by dehydrohalogenation either thermally or catalytically. Another route for conversion of the by-product ethyl chloride to produce additional vinyl chloride involves dehydrohalogenation to ethylene followed by oxychlorination of this hydrocarbon directly to the desired vinyl chloride or conversion of ethylene to produce 1,2-dichloroethane which on pyrolysis yields vinyl chloride. Not much attention has been given to direct production of vinyl chloride from ethyl chloride by dehydrogenation of the ethyl chloride although in U.S. Pat. No. 3,356,750 such a process is described. According to this patent, a haloalkane having 2 to 4 carbon atoms such as ethyl chloride is dehydrogenated by passing it in admixture with oxygen and molecular iodine at a temperature in the range from 400.degree. C. to 800.degree. C. and at a partial pressure of halogen-containing alkane equivalent to less than about 15 inches of mercury through a reactor containing metals or active compounds thereof of Groups I-A, II-A, II-B, III-A, III-B, IV-A, IV-B, V-A, V-B, VI-B, VII-B, VIII and the lanthanum rare earth group of the Periodic Table. While a high yield of vinyl chloride is said to be obtained with this method, the problems of handling the highly volatile and corrosive iodine reactant are formidable when practicing this process on a commercial scale. Accordingly, it is an object of the present invention to provide a process for dehydrogenation of ethyl chloride to vinyl chloride which operates at somewhat lower temperatures, eliminates iodine as a reactant and yet provides comparable high yields of vinyl chloride in view of the excellent selectivity of a novel catalyst which has been discovered. In addition to providing a means for converting to vinyl chloride the ethyl chloride obtained as a by-product in chlorination reactions, the process of the invention provides a means for producing vinyl chloride from ethane as the hydrocarbon source instead of ethylene.